Willy Hijmans

Admission criteria for immunogerontological studies in man: the SENIEUR protocol

Immunogerontological studies in man have often led to conflicting results. One of the main reasons is the selection of the subjects to be studied. Admission criteria such as apparently healthy or without overt disease seem insufficient to exclude underlying disease which might influence the immune system and thereby the results. In an attempt to solve this problem, the SENIEUR protocol described in this paper was developed by a working party in the framework of the EURAGE Concerted Action Programme on Ageing of the European Community. This protocol establishes strict admission criteria for immunogerontological studies in man based on clinical information and laboratory data, and it sets limits to pharmacological interference. The use of this protocol will lead to standardization between centers and also to a closer study of the influence of age as such on the immune system. These findings in the immunologically optimally aged can also serve as reference values for immunogerontological studies in subjects who do not meet the SENIEUR criteria. In this way the use of this protocol can contribute to the dissection of the influence of disease versus ageing on the immune system.

Necessity of the assessment of health status in human immunogerontological studies: Evaluation of the senieur protocol

Disease is frequent in ageing, and the many conflicting results in studies of the ageing process can be due to the presence of factors such as underlying disease or the use of medication. For immunogerontology, a solution to this problem was initiated in 1984 by a working party of EURAGE, the European Communitys Concerted Action Programme on Ageing and Diseases. A protocol defining strict admission criteria to studies of ageing, the SENIEUR protocol, was elaborated. This protocol intends to limit the influence of disease and/or medication and to standardize admission criteria to immunogerontological studies. In subjects fulfilling the SENIEUR criteria, we found less immunological defects with ageing than generally stated. This could mean that many studies performed in not-optimally healthy subjects describe defects that are not a consequence of the ageing process, but could be a result of underlying disease or of the influence of medication. For lymphocyte subsets, certain changes are only found in the comparison of SENIEUR groups of young and aged, while other changes are only found when non-healthy groups are compared. The occurrence of monoclonal gammopathies and autoantibodies was increased in ageing, but was also influenced by health status. Experience of other groups, and the objections against the protocol are discussed.

AN IMMUNOFLUORESCENCE STUDY ON INTRACELLULAR IMMUNOGLOBULINS IN HUMAN BONE MARROW CELLS

Previous papers1p2 reported results obtained in testing conjugated antisera for their capacity to recognize the individual heavy and light chains of human immunoglobulins. In these tests bone marrow preparations were used from patients suffering from multiple myeloma and Waldenstrom’s macroglobulinemia. I t has already been shown that these tissues synthesized the corresponding M-component and that the tumor cells in these specimens do contain this M-c~mponent.~ In the course of these analyses a large number of bone marrow specimens from persons with and without M-components were investigated and the results are presented in this paper.

Prevalence of Dementia in the ‘Oldest Old’ of a Dutch Community

To estimate the prevalence rate of dementia in subjects 85 years of age and over.

Autoantibodies in highly aged humans

The presence of 14 different autoantibodies was determined in 65 persons, aged 95 years and older, without overt disease. The prevalence of positive anti-immunoglobulin latex tests, of autoantibodies against nuclear components and against thyroid microsomes was significantly increased. This selective increase of autoantibodies of low titre and without cluster formation is considered to be the result of a loss of control within the immune system due to ageing, rather than as a sign of latent disease.

Longevity and Heredity in Humans

Several arguments support the idea of a link between longevity and heredity, both in experimental animals and in the human species. In mice, genes in the major histocompatibility complex (MHC) are associated with a significant effect on life span. Results of analogous studies in man are confusing and contradictory. We have therefore investigated the question of an association of the human leucocyte antigen (HLA) and longevity in a large and ethnically homogeneous population. Our study population consisted of all 964 available inhabitants aged 85 years and over in the Dutch community of Leiden (pop. 104,000). Our control group comprised 2444 young inhabitants, aged 20-35 years, with an identical ethnic and demographic background. In addition, control groups of different age-brackets from the same region were used. Two antigens differed in frequency: HLA-B40 was lower and HLA-DR5 was higher in the group of 85 years and over, as compared to the control group, aged 20-35 years. Both differences were more evident in females. No major disease associations with HLA-B40 or HLA-DR5 have been reported. It is unlikely that these results are a chance observation: the overall similarity of the HLA pattern of the old and young age groups is a confirmation of their identical ethnic and demographic background and the changes as observed in the different age-groups were gradual. The biological meaning of these results is still unclear.

Intracellular inclusion bodies in 14 patients with B cell lymphoproliferative disorders.

Two types of intracytoplasmic inclusion were detected by immunofluorescence microscopy in 12 patients with chronic lymphocytic leukaemia and two patients with a leukaemic phase of well differentiated lymphocytic lymphoma. Further analysis with light- and electron microscopy, showed that most inclusion bodies were rod-like crystalline structures. However, in three patients they consisted of amorphous vesicular precipitates. Immunological studies revealed the presence of immunoglobulins of the same class and type at the cell surface as well as in the inclusion bodies. The monoclonal immunoglobulins were all of lambda type except in two cases. The origin of immunoglobulin inclusion bodies in B cell malignancies is discussed in relation to published data and our own observation in one patient followed during treatment.

The cellular basis of double paraproteinemia in man

Abstract Bone marrow samples of 16 individuals with double paraproteinemia were studied with immunofluorescence to investigate the cellular origin of these M components. In confirmation of the data in the literature was the finding of separate cell populations in the majority of cases. In some, the findings indicated a second possibility, in which both paraproteins were synthesized by the cells of one clone. In addition, evidence for a third alternative, in which a proliferation of “switch” precursor cells leads to the formation of two clones, was found.

The prevalence of morbidity in the oldest old, aged 85 and over: a population-based survey in Leiden, The Netherlands.

The Leiden 85-plus study has investigated the prevalence of morbidity in the total population of the Dutch community of Leiden (population 105 000) aged 85 and over, including both independently living and institutionalized elderly. The participation rate of 94% of all living elderly (n = 1037) and 78% of the initial cohort (n = 1259) was exceptionally high. Information was obtained on past and present diseases by taking a medical history. The life-time prevalence for arteriosclerosis and malignancies was 31.9% and 9.7% respectively. High prevalences were found for the non-lethal disabling disorders of hearing and visual impairment (44.4% and 49.9%, respectively) and urinary incontinence (25.6%). The authors conclude that establishing a classical medical diagnosis in the oldest old, which was the goal of this study, is not complete without assessing its effect on the functional ability and the quality of life of the individual.

MICROFLUOROMETRIC EVALUATION OF CONJUGATE SPECIFICITY WITH THE DEFINED ANTIGEN SUBSTRATE SPHERES (DASS) SYSTEM

Six fluorescent antihuman Ig preparations were tested for their Ig class specificity by reacting them with highly purified IgG, IgM, IgA, and OVA coupled covalently to Sepharose beads. OVA was used as a measure for nonimmunologic binding. Bead fluorescence was determined by microfluorometry. The amounts of USS and NSS were expressed quantitatively. These data were compared with the performance of these particular conjugates in a biologic system, namely, monoclonal bone marrow cells. Five of the six conjugates satisfied the requirement of monospecific activity; one did not. At a dilution of 1 : 8, the five monospecific conjugates reacted between five and 50 times stronger with their appropriate antigens than with OVA-coupled beads. Cross reactivity with other Ig classes, after correction for OVA staining was maximally 6%. The conjugate that was nonspecific in the bone marrow system gave very high cross reactivity with the Ig-coupled beads. A good correlation was found between OVA bead staining and nonimmunologic binding of conjugates in bone marrow slides. In this respect, conjugates prepared from antibody preparations isolated by solid immunoadsorbents proved to be superior to globulin or whole IgG fractions. Ig coupled to Sepharose beads seems to represent a very promising substrate for conjugate specificity testing.